Well you can test that. Send a mail from it to a hotmail address and view the email headers when you receive it in hotmail. One of the first lines will be a Received: from mx1.domain.co.uk ([194.nn.nn.nn]) type format...
I just had the owner of my IP address setup my PTR record. It was a completely different company to my ISP, but they set it up very quickly for us. And immediately afterwards, aol emails started working.
I did some tests via manual telnet SMTP on my mail gateway.
First, I used nslookup to get an aol MX mailserver... mailin-01.mx.aol.com
ie... nslookup
set type=mx
aol.com
exit
Our conversations went like this:
(
Blue writing is my commands)
(
Red writing is aol responses)
(the "peer name unknown" is the telling part)
----------- BEFORE PTR RECORD SET UP ---------------
CODE
telnet mailin-01.mx.aol.com 25
220-rly-xg06.mx.aol.com ESMTP mail_relay_in-xg6.3; Tue, 12 Jul 2005 13:44:13 -0400
220-America Online (AOL) and its affiliated companies do not
220- authorize the use of its proprietary computers and computer
220- networks to accept, transmit, or distribute unsolicited bulk
220- e-mail sent from the internet. Effective immediately: AOL
220- may no longer accept connections from IP addresses which
220 have no reverse-DNS (PTR record) assigned.
ehlo mydomain.co.uk
250-rly-yg05.mx.aol.com peer name unknown
250 HELP
mail from:<nickpark@mydomain.co.uk>
250 OK
rcpt to:<test.user@aol.com>
250 OK
data
354 START MAIL INPUT, END WITH "." ON A LINE BY ITSELF
hello
.
421-: (DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
421 SERVICE NOT AVAILABLE
----------- AFTER PTR RECORD SET UP ---------------
CODE
telnet mailin-01.mx.aol.com 25
220-rly-xg06.mx.aol.com ESMTP mail_relay_in-xg6.3; Tue, 12 Jul 2005 17:46:15 -0400
220-America Online (AOL) and its affiliated companies do not
220- authorize the use of its proprietary computers and computer
220- networks to accept, transmit, or distribute unsolicited bulk
220- e-mail sent from the internet. Effective immediately: AOL
220- may no longer accept connections from IP addresses which
220 have no reverse-DNS (PTR record) assigned.
ehlo mydomain.co.uk
250-rly-xg06.mx.aol.com mx1.mydomain.co.uk
250 HELP
mail from:<nickpark@mydomain.co.uk>
250 OK
rcpt to:<testuser@aol.com>
250 OK
data
354 START MAIL INPUT, END WITH "." ON A LINE BY ITSELF
hello
.
250 OK
quit
221 SERVICE CLOSING CHANNEL
Connection to host lost.
Does your NSLOOKUP work and do you get the "peer name unknown" when you say 'EHLO'?